BACKGROUND: Despite that over 90 million pregnancies are at risk
of Plasmodium vivax infection annually, little is known about
the epidemiology and impact of the infection in pregnancy.
METHODOLOGY AND PRINCIPAL FINDINGS: We undertook a health
facility-based prospective observational study in pregnant women
from Guatemala (GT), Colombia (CO), Brazil (BR), India (IN) and
Papua New Guinea PNG). Malaria and anemia were determined during
pregnancy and fetal outcomes assessed at delivery. A total of
9388 women were enrolled at antennal care (ANC), of whom 53%
(4957) were followed until delivery. Prevalence of P. vivax
monoinfection in maternal blood at delivery was 0.4% (20/4461)
by microscopy [GT 0.1%, CO 0.5%, BR 0.1%, IN 0.2%, PNG 1.2%] and
7% (104/1488) by PCR. P. falciparum monoinfection was found in
0.5% (22/4463) of women by microscopy [GT 0%, CO 0.5%, BR 0%, IN
0%, PNG 2%]. P. vivax infection was observed in 0.4% (14/3725)
of placentas examined by microscopy and in 3.7% (19/508) by PCR.
P. vivax in newborn blood was detected in 0.02% (1/4302) of
samples examined by microscopy [in cord blood; 0.05% (2/4040) by
microscopy, and 2.6% (13/497) by PCR]. Clinical P. vivax
infection was associated with increased risk of maternal anemia
(Odds Ratio-OR, 5.48, [95% CI 1.83-16.41]; p = 0.009), while
submicroscopic vivax infection was not associated with increased
risk of moderate-severe anemia (Hb<8g/dL) (OR, 1.16, [95% CI
0.52-2.59]; p = 0.717), or low birth weight (<2500g) (OR,
0.52, [95% CI, 0.23-1.16]; p = 0.110). CONCLUSIONS: In this
multicenter study, the prevalence of P. vivax infection in
pregnancy by microscopy was overall low across all endemic study
sites; however, molecular methods revealed a significant number
of submicroscopic infections. Clinical vivax infection in
pregnancy was associated with maternal anemia, which may be
deleterious for infant's health. These results may help to guide
maternal health programs in settings where vivax malaria is
endemic; they also highlight the need of addressing a vulnerable
population such as pregnant women while embracing malaria
elimination in endemic countries.